This research will seek to delineate the biochemical mechanisms in ocular epithelial tissues by which the intracellular concentration of cyclic 3',5'-AMP (c-AMP) is regulated and how the resulting level of c-AMP is correlated temporally with ion movement. These investigations will use, primarily, isolated cell types obtained by enzymmtic digestion followed by density gradient centrifugation. These types of rabbit epithelial tissues will be examined: Those associated with a rich blood supply (pigmented and nonpigmented epithelial cells from ciliary process tissues, pigmented epithelial cells from the retina, epithelial cells from choroid plexus of the brain and isolated collecting tubules from the kidney cortex); those with no vascular association (endothelial and epithelial cells from the cornea); and those without blood supply or innervation (lens epithelial cells). Studies will continue using isolated cells prelabeled simultaneously with (C14)-adenine and (14C)-dihomo-gamma-linolenic acid with subsequent isolation and counting of synthesized (14C)-c-AMP and (14C)-prostaglandins (PGs) along with tracer (H3)-c-AMP and (3H)-PGs for recovery correction. Effects of added cyclic nucleotides or PGs upon endogenous levels will be examined as well as adrenergic and cholinergic drugs. Interesting observation will be backed up by adenylate cyclase and c-AMP phosphodiesterase assays. Some ocular epithelial tissues of rabbits with hereditary buphthalmia will also be examined.